Zinc-essential for flora and fauna

ABSTRACT

The present invention relates to a chelated fertilizer composition for enriching Zinc and Phosphorus content in agriculture/horticulture crops and plants through foliar application. The chelated fertilizer composition can be prepared using compounds comprising (a) Na2 HEDP and ZnSO4.H2O (Zinc sulphate monohydrate) and (b) Na2 HEDP and ZnO (Zinc Oxide). The chelation of Zn by Na2 HEDP using ZnSO4.H2O developed 17% Zn-HEDP and 21% Phosphorus pentoxide (P2O5) and chelation of Zn by Na2 HEDP using ZnO developed 21% Zn-HEDP and 26% P2O5. The chelated fertilizer composition obtained is in powder form and is 100% water-soluble concentrate. The chelated fertilizer composition can be used to cure Zinc and Phosphorus deficiency in crops and plants, increase yield with more Zinc and Phosphorus content, thus reducing the risk of Zinc and Phosphorus deficiency in humans.

FIELD OF INVENTION

The present invention relates to a chelated fertilizer composition for agriculture/horticulture crops and plants. More specifically, the present invention relates to a chelated fertilizer composition for enriching Zinc and Phosphorus content in crops and plants through foliar application. Further, the present invention relates to a method of preparing the chelated fertilizer composition. The chelated fertilizer composition can be used to cure Zinc and Phosphorus deficiency in crops and plants, increase yield with more Zinc and Phosphorus content, thus reducing the risk of Zinc and Phosphorus deficiency in humans.

DESCRIPTION OF PRIOR ART

Zinc (Zn) is an essential micronutrient in crop/plant production and is used in many fertilizers. Some soil can supply the adequate amount of zinc to plants. In other cases where Zn exists in the soil in an unavailable form or the soil is Zn deficient, Zn fertilizers may be added to the soil to enrich soil fertility. Plants vary considerably in their requirement for Zn. Zn is an important component of various metallo enzymes such as carbonic anhydrase, alcohol dehydrogenase etc that are responsible for driving various metabolic reactions in plants. Zn is essential for the biosynthesis of the plant hormone indole acetic acid (IAA). Zn also plays a role in nucleic acid, protein synthesis and helps in the utilization of phosphorus and nitrogen in plants. Absence of Zn can affect growth and development in plants. Plants deficient in Zn show certain characteristic deficiency symptoms that may last through the entire growth season.

Though required in small quantities, Zn is also very essential for humans. Plant sources for Zn include cereals, nuts, legumes, soy products etc. In humans, Zn deficiency can cause appearance of white spots on nails, skin lesions, acne, diarrhea, wasting of body tissues etc. Zn plays an essential role in eyesight, taste, smell and memory. Deficiency in Zn can cause malfunctions of these organs and functions. Zn is an essential component in many enzymes and influences hormones. Zn also accelerates cell division and enhances the immune system. Congenital abnormalities causing Zn deficiency may lead to a disease called acrodermatitis enteropathica, a metabolic disorder affecting the uptake of Zn. Enriching plants used as food source with Zn helps to combat Zn deficiency in humans.

The importance of Zn has lead to the research in use of Zn in the sequestered form. Normally, cationic nutrients are fixed by anions. This leads to chelation i.e., sequestering. Once chelated, fixation and unwanted reaction will not affect. The chelation process will enable the nutrients to move freely inside the plants. Known in Prior Art is chelation of Zn using Ethylene diamine tetra acetic acid (EDTA) to give Zn EDTA. This sequestered form of Zn is used in agriculture as a micronutrient for plant growth. However, Zn EDTA gives only 12% Zn.

U.S. Pat. No. 5,047,078 describes a fertilizer composition comprising a phosphate fertilizer and a kale inhibiting compound that helps to increase plant growth and yield.

US20110098177 relates to a method of providing a metal to a plant to increase the yield.

US20030101785 describes micronutrient compositions having chelated metal ions. The chelating agents used are amino phosphonic acids.

US20080293570 describes a method of sequestering micronutrients to provide the micronutrients to a plant.

AU2006200467 relates to micronutrient chelate fertilizers and methods for preparing the same.

Accordingly, there exist a need for a fertilizer composition for improving the nutrient content in crops and plants, thereby overcoming the problems associated with nutrient deficiencies.

OBJECTS OF INVENTION

The primary object of the present invention is directed to provide a chelated fertilizer composition for agriculture/horticulture crops and plants.

It is another object of the present invention to provide a chelated fertilizer composition for enriching Zinc (Zn) and Phosphorus (P) content in crops and plants through foliar application.

It is another object of the present invention to provide a method of preparing the chelated fertilizer composition.

It is another object of the present invention, wherein the chelated fertilizer composition is used to cure Zn and P deficiency in crops and plants, increase yield with more Zn and P content, thus reducing the risk of Zn and P deficiency in humans.

It is another object of the present invention, wherein sequestration of Zn is done using a chelating agent—disodium salt of Hydroxy Ethylidene Di Phosphonic Acid (Na₂ HEDP).

It is another object of the present invention, wherein the chelated fertilizer composition can be prepared using compounds comprising Na₂ HEDP and ZnSO₄.H₂O (Zinc sulphate monohydrate).

It is another object of the present invention, wherein the chelated fertilizer composition can be prepared using compounds comprising Na₂ HEDP and ZnO (Zinc Oxide).

It is another object of the present invention, wherein chelation of Zn by Na₂ HEDP using ZnSO₄.H₂O developed 17% Zn-HEDP and 21% Phosphorus pentoxide (P₂O₅).

It is another object of the present invention, wherein chelation of Zn by Na₂ HEDP using ZnO developed 21% Zn-HEDP and 26% P₂O₅.

It is another object of the present invention, wherein the Zn-HEDP increases the yield upto 27% and the Zn content is increased upto 85% in Grains compared to control.

It is another object of the present invention, wherein the P₂O₅ increases the yield and Phosphorous concentration of crops and plants.

It is another object of the present invention, wherein the chelated fertilizer composition obtained is in powder form and is 100% water-soluble concentrate.

SUMMARY OF INVENTION

Thus according to the basic aspect of the present invention, there is provided a chelated fertilizer composition for use as a foliar fertilizer for enrichment of Zinc (Zn) and Phosphorus (P) in crops and plants comprising:

-   -   Zinc (Zn) chelate; and     -   Phosphorus pentoxide (P₂O₅),     -   wherein the Zinc chelate is Zn-Hydroxy Ethylidene Di Phosphonic         Acid (HEDP), and     -   wherein the chelated fertilizer composition is in powder form         and is 100% water soluble concentrate.

A further aspect of the present invention is directed to provide a chelated fertilizer composition, wherein the fertilizer composition is prepared using compounds comprising:

-   -   Chelating agent; and     -   Zinc sulphate monohydrate (ZnSO₄.H₂O),     -   wherein the chelating agent is disodium salt of Hydroxy         Ethylidene Di Phosphonic Acid (Na₂ HEDP).

A further aspect of the present invention is directed to provide a chelated fertilizer composition, wherein the fertilizer composition is prepared using compounds comprising:

-   -   Chelating agent; and     -   ZnO (Zinc Oxide),     -   wherein the chelating agent is disodium salt of Hydroxy         Ethylidene Di Phosphonic Acid (Na₂ HEDP).

It is another aspect of the present invention, wherein the Zinc chelate (Zn-Hydroxy Ethylidene Di Phosphonic Acid) is obtained by sequestration of Zinc (Zn) using the chelating agent.

It is another aspect of the present invention, wherein the chelated fertilizer composition in powder form contains 17% Zn-HEDP and 21% P₂O₅ by weight of the composition.

It is another aspect of the present invention, wherein the chelated fertilizer composition in powder form contains 21% Zn-HEDP and 26% P₂O₅ by weight of the composition.

It is another aspect of the present invention, wherein pH of the chelated fertilizer composition is between 3.5 and 4.5.

A further aspect of the present invention is directed to provide a process for preparing the chelated fertilizer composition using compounds comprising disodium salt of Hydroxy Ethylidene Di Phosphonic Acid (Na₂ HEDP) and ZnSO₄.H₂O (Zinc sulphate monohydrate), comprising the steps of:

-   -   Dissolving Na₂ HEDP in water;     -   Heating the dissolved mixture up to 100° C. in a non-stick         temperature controlled vessel/reactor;     -   Adding ZnSO₄.H₂O slowly and stirring to obtain mixture         containing Zn-HEDP and P₂O₅;     -   Maintaining the temperature at 100° C. and stirring the mixture         until liquid portion evaporates; and     -   Drying the composition thus obtained using drier to secure         moisture free powder composition containing 17% Zn-HEDP and 21%         P₂O₅,     -   wherein the chelated fertilizer composition is in powder form         and is 100% water soluble concentrate.

A further aspect of the present invention is directed to provide a process for preparing the chelated fertilizer composition using compounds comprising disodium salt of Hydroxy Ethylidene Di Phosphonic Acid (Na₂ HEDP) and ZnO (Zinc Oxide), comprising the steps of:

-   -   Dissolving Na₂ HEDP in water;     -   Heating the dissolved mixture up to 100° C. in a non-stick         temperature controlled vessel/reactor;     -   Adding ZnO slowly and stirring to obtain mixture containing         Zn-HEDP and P₂O₅;     -   Maintaining the temperature at 100° C. and stirring the mixture         until liquid portion evaporates;     -   Drying the composition thus obtained using drier to secure         moisture free powder composition containing 23% Zn-HEDP and 29%         P₂O₅;     -   Adding 10% dispersal powder; and     -   Mixing in blender to obtain 21% Zn-HEDP and 26% P₂O₅,     -   wherein the chelated fertilizer composition is in powder form         and is 100% water soluble concentrate.

BRIEF DESCRIPTION OF THE FLOWCHARTS

FIG. 1 is a flowchart illustrating the process for preparing the chelated fertilizer composition using Na₂ HEDP and ZnSO₄.H₂O.

FIG. 1 is a flowchart illustrating the process for preparing the chelated fertilizer composition using Na₂ HEDP and ZnO.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention relates to a chelated fertilizer composition for agriculture/horticulture crops and plants, and a method of preparing the chelated fertilizer composition. The present invention provides a chelated fertilizer composition for enriching Zinc (Zn) and Phosphorus (P) content in crops and plants through foliar application. Zn-HEDP increases the yield up to 27% and the Zn content is increased up to 85% in grains compared to control.

The chelated fertilizer composition is used to cure Zn and P deficiency in crops and plants, increase yield with more Zn and P content, thus reducing the risk of Zn and P deficiency in humans. The sequestration of Zn is done using a chelating agent—disodium salt of Hydroxy Ethylidene Di Phosphonic Acid (Na₂ HEDP). The chelated fertilizer composition can be prepared using either compounds comprising Na₂ HEDP and ZnSO₄.H₂O (Zinc sulphate monohydrate), or compounds comprising Na₂ HEDP and ZnO (Zinc Oxide). The Zn chelate increases the yield and Zn concentration and P₂O₅ increases the yield and Phosphorous concentration of crops and plants.

In one embodiment of the present invention, the chelated fertilizer composition is obtained using. Na₂ HEDP and ZnSO₄.H₂O, heated at 100° C. to give 17% Zn-HEDP and 21% P₂O₅ in powder form as shown below. The chelated fertilizer composition thus obtained is completely soluble.

The process of preparing the chelated fertilizer composition as illustrated in the flow chart of FIG. 1 using Na₂ HEDP and ZnSO₄.H₂O comprises dissolving 90 Kg Na₂ HEDP in water. 90 Kg Na₂ HEDP contains 40.89 gram P₂O₅. The dissolved mixture is heated up to 100° C. in a non-stick temperature controlled vessel/reactor or open pan. Further 100 Kg ZnSO₄.H₂O containing 33 gram Zn is slowly added and the mixture is stirred. During this process, the temperature is maintained at 100° C. and the mixture stirred for 4-5 hours until the liquid portion evaporates. The composition thus obtained is dried using mechanical/automatic drier to secure moisture free powder containing 17% Zn HEDP and 21% P₂O₅. Chelation makes the composition completely soluble. The composition is analyzed and packed for market. The pH of the chelated fertilizer composition is between 3.5 and 4.5.

Lab Grade ZnSO₄.H₂O—2.27 gm Zinc—5 gm 100% HEDP,

whereas in prior art:

Lab Grade ZnSO₄.H₂O—2.27 gm Zinc—11.13 gm EDTA

The method of preparing the chelated fertilizer composition using Na_(e) HEDP and ZnSO₄.H₂O is summarized as follows:

In another embodiment of the present invention, the chelated fertilizer composition is obtained using Na₂ HEDP and ZnO, heated at 100° C. to give 21% Zn-HEDP and 26% P₂O₅ in powder form as shown below. The chelated fertilizer composition thus obtained is completely soluble.

The process of preparing the chelated fertilizer composition as illustrated in the flow chart of FIG. 2 using Na₂ HEDP and ZnO comprises dissolving 187 Kg Na₂ HEDP in water. 187 Kg Na₂ HEDP contains 85 Kg P₂O₅. The dissolved mixture is heated up to 100° C. in a non-stick temperature controlled vessel/reactor or open pan. Further, 100 Kg ZnO containing 68 Kg Zn is slowly added and the mixture is stirred. During this process, the temperature is maintained at 100° C. and the mixture stirred for 4-5 hours until the liquid portion evaporates. The composition thus obtained is dried using mechanical/automatic drier to secure moisture free powder containing 23% Zn-HEDP and 29% P₂O₅. 10% dispersal powder is added and mixed well in mechanical blender to obtain 21% Zn-HEDP and 26% P₂O₅. Chelation makes the composition completely soluble. The composition is analyzed and packed for market. The pH of the chelated fertilizer composition is between 3.5 and 4.5.

The method of preparing the chelated fertilizer composition using Na₂ HEDP and ZnO is summarized as follows:

2.27 gm Zinc needs 5 gm 100% HEDP

2.27 gm Zinc needs 6.25 gm Na₂ HEDP

${{{Zn}\text{-}{HEDP}} - {\frac{68}{287} \times 100}}->{23\%\mspace{14mu}{Zn}\text{-}{HEDP}}$ ${{P_{2}O_{5}} - {\frac{85}{287} \times 100}}->{29\%\mspace{14mu} P_{2}O_{5}}$

The chelated fertilizer composition Obtained by adding 10% dispersal is

$\left. {{{Zn}\text{-}{HEDP}} - {\frac{68}{316} \times 100}}\;\rightarrow\;{21\%\mspace{14mu}{Zn}\text{-}{HEDP}} \right.$ $\left. {{P_{2}O_{5}} - {\frac{85}{316} \times 100}}\rightarrow{26\%\mspace{14mu} P_{2}O_{5}} \right.$

Various field experiments were conducted to study the effect of Zn-HEDP chelate on plants.

Experiment I

Field Experiments in wheat was carried out using the composition of the present invention for two consecutive years in Punjab Agriculture University (PAU) Research Farm and Framer's field (Jattpur) loamy soil. Wheat cultivar PBW 550 seeds were sown during the first week of November. Two Zn chelates at different concentrations at two stages of wheat plant growth were applied through foliar application. In another treatment, Zn was added to the soil as basal dose at 62.5 kg ha⁻¹ using ZnSO_(4.)7H₂O salt. The first application of Zn chelate spray was done at maximum tillering stage and the second application was made at panicle initiation stage. The different treatments are shown in Table 1. Various parameters like plant height, tillers and 1000-grain weight were noted. Additionally during maturity in the month of April, the wheat grain and straw yield were noted.

TABLE 1 Different Zinc chelate treatments used for the above experiment Concentration of Treatments Name of Chemical/Chelate Chemical/Chelate T₁ ZnSO₄•7H₂O (soil application) 62.5 kg ha⁻¹ T₂ Zn HEDP (C) (foliar spray) 2 gram liter⁻¹ T₃ Zn HEDP (C) (foliar spray) 3 gram liter⁻¹ T₄ Zn HEDP (L) (foliar spray) 2 gram liter⁻¹ T₅ Zn HEDP (L) (foliar spray) 3 gram liter⁻¹ T₆ No Zn (Control) Nil

The physio-chemical analyses of the soil before the start of the experiment was carried out at the two locations were the experiments were to be carried. The soil properties of the experimental fields before the start of the experiment are shown in Table 2.

TABLE 2 Soil properties of the experimental fields before the start of the experiment Soil Properties Texture PAU research Farmer's field farm sandy loam (Jattpur) loamy sand pH (1:2:: soil:water) 7.5 7.8 Electric Conductivity (dS m⁻¹) 0.16 0.12 Organic Carbon (%) 0.46 0.30 Available Nitogen (kg ha⁻¹) 280 240 Available Phosphorus (kg ha⁻¹) 18.0 15.4 Available Potassium (kg ha⁻¹) 285 260 Available Zinc (mg kg⁻¹) 0.86 0.52

The plant parameters in wheat under different Zn treatments at PAU research farm and farmer's field are shown in Table 3 and Table 4 respectively and grain and straw yields in wheat under different Zn treatments at PAU research farm and farmer's field are shown in Table 5 and Table 6 respectively.

TABLE 3 Plant parameters in wheat under different Zn treatments at PAU research farm Rabi 2009-2010 Rabi 2010-2011 Tillers 1000 Tillers 1000 Plant per grains Plant per grains height square weight height square weight Treatment (cm) meter (g) (cm) meter (g) T₁ 76.7 293 38.4 97.69 377 38.7 T₂ 76.1 291 36.8 95.23 372 36.9 T₃ 77.4 294 38.4 96.20 381 39.2 T₄ 79.6 287 37.6 95.90 373 38.1 T₅ 78.0 295 38.7 96.81 383 39.8 T₆ 74.2 275 34.4 93.65 357 35.5 Mean 76.9 289 37.4 95.91 373 38.0 CD (0.05) 4.2 9.5 2.9 NS NS 2.51

TABLE 4 Plant parameters in wheat under different Zn treatments at farmer's field Rabi 2009-2010 Rabi 2010-2011 Tillers 1000 Tillers 1000 Plant per grains Plant per grains height square weight height square weight Treatment (cm) meter (g) (cm) meter (g) T₁ 76.6 272 35.1 74.7 353 34.3 T₂ 71.9 254 34.9 68.1 320 33.4 T₃ 75.9 255 33.9 73.3 333 33.8 T₄ 76.2 261 33.7 69.9 318 32.7 T₅ 73.6 266 33.3 70.7 340 33.2 T₆ 72.0 248 31.1 66.7 290 30.8 Mean 74.4 259 33.7 70.6 326 33.0 CD (0.05) 4.0 10.1 1.9 4.02 6.28 0.75

TABLE 5 Grain and Straw yields (q ha⁻¹) in wheat under different Zn treatments at PAU research farm Rabi 2009-2010 Rabi 2010-2011 % increase % increase % increase % increase Treatments Grain over control Straw over control Grain over control Straw over control T₁ 52.5 10.8 65.0 3.7 54.4 13.3 65.7 5.5 T₂ 51.0 7.6 65.4 4.3 50.5 5.2 66.9 7.4 T₃ 51.2 8.0 67.6 7.8 51.5 7.3 69.6 11.7 T₄ 48.8 3.0 64.6 3.0 52.2 8.8 73.9 18.6 T₅ 52.0 9.7 66.7 6.4 53.4 11.3 74.1 18.9 T₆ 47.4 0.0 62.7 0.0 48.0 0.0 62.3 0.0 Mean 50.5 6.5 65.3 4.2 51.7 7.6 68.8 10.4 CD (0.05) 3.6 — 4.4 — 2.90 — NS —

TABLE 6 Grain and Straw yields (q ha⁻¹) in wheat under different Zn treatments at farmer's field Rabi 2009-2010 Rabi 2010-2011 % increase % increase % increase % increase Treatments Grain over control Straw over control Grain over control Straw over control T₁ 46.7 28.7 55.3 9.1 46.0 28.5 54.7 20.8 T₂ 45.0 24.0 56.0 10.5 43.2 20.7 48.5 7.1 T₃ 46.0 26.7 58.3 15.0 44.7 24.9 50.3 11.0 T₄ 44.3 22.0 52.3 3.2 43.0 20.1 49.3 8.8 T₅ 46.3 27.5 59.0 16.4 45.6 27.4 52.5 15.9 T₆ 36.3 0.0 50.7 0.0 35.8 0.0 45.3 0.0 Mean 44.1 21.5 55.3 9.0 43.1 20.3 50.1 10.6 CD (0.05) 2.52 — 2.37 — 2.25 — NS —

Experiment II

Field Experiments in wheat was carried out using the composition of the present invention in the soils of the irrigated north-west plain zone of Rajasthan. The soils of north-west plain zone are deficient in zinc and poor growth or deficiency symptoms appear on the wheat crops. The different treatments used for Experiment II are shown in Table 7. Two foliar sprays were applied. First, during the vegetative growth stage on early appearance of the deficiency symptoms and the second foliar spray during the flag leaf initiation stage of the wheat crop.

TABLE 7 Different Zinc chelate treatments used for experiment II NAME OF CHEMICAL/ CONCENTRATION OF TREATMENTS CHELATE CHEMICAL/CHELATE T₁ No Zn (Control) Nil T₂ Zn HEDP (C) (foliar spray) 2 gram liter⁻¹ of water T₃ Zn HEDP (C) (foliar spray) 3 gram liter⁻¹ of water T₄ Zn HEDP (L) (foliar spray) 2 gram liter⁻¹ of water T₅ Zn HEDP (L) (foliar spray) 3 gram liter⁻¹ of water T₆ ZnSO₄ 24 kg ha⁻¹

The soil of the irrigated north-west plain zone of Rajasthan has a pH, of 8.27 and electric conductivity was 0.20 dS^(−m). The soil has an organic carbon content of 0.23%, which is low, medium in available P₂O₅ i.e. 25.0 kg ha⁻¹ and high in available K₂O i.e. 250 kg ha⁻¹. The diethylene triamine pentaacetic acid (DTPA) extractable zinc concentration in the soil was low. The wheat grain and straw yield were increased with the foliar application of Zn chelate at lower concentration Zn-HEDP (C) −2 gram liter⁻¹ of water. Other ancillary characters such as tillering and ear length significantly increased over the control treatment as shown in Table 8. The foliar application significantly increased thousand grain weights over the control treatment.

TABLE 8 Effect of the Zn chelate on yield and ancillary parameters of wheat crops No. of 1000 Zn tillers m⁻¹ Grain Ear conc Yield (tonne ha⁻¹) row weight length (mg Treatments Grain Straw length (g) (cm) kg⁻¹) T₁ 4.13 5.20 112 35.60 9.28 23.50 T₂ 4.56 6.61 123 40.53 10.10 38.25 T₃ 4.50 6.52 115 38.43 9.93 32.00 T₄ 4.34 6.80 117 40.05 10.43 31.50 T₅ 4.42 6.58 116 39.68 10.08 30.50 T₆ 4.57 6.61 122 39.73 10.18 30.25 SEM 0.10 0.25 2.95 1.08 0.19 2.20 C.D. at 5% 0.31 0.74 8.88 3.25 0.58 6.60

Experiment III

Field experiments in transplanted rice were carried out using the composition of the present invention in Krishna-Godavari zone of Coastal Andhra Pradesh during rabi, 2008-2009. The climate conditions prevailing in this region are tropical, subtropical, humid to sub humid climate. The composition of the present invention (Zn-HEDP) was applied at two levels i.e. at 1 g and 2 g per liter to be sprayed at three stages 20, 40 and 60 days after transplanting rice crop. The prior art composition Zn-EDTA is also compared at similar doses of 1 g and 2 g in one liter water and also sprayed at 20, 40 and 60 days. Table 9 shows the effect of the above Zn compositions on rice grain and straw yields and Table 10 shows the effect of zinc compositions on yield components of rice.

TABLE 9 Effect of Zn compositions on rice grain and straw yields Plant Grain Straw Total ht. yield yield biomass S. No Treatment (cm) (kg/ha) (kg/ha) (kg/ha) T1 Zn HEDP@ 1 g/lt. 91.30 5717 4816.5 10558 T2 Zn HEDP @ 2 g/lt. 97.28 6005 5287.5 11210 T3 Zn EDTA @ 1 g/lt. 90.80 5630 4895.5 10405 T4 Zn EDTA @ 2 g/lt. 94.80 5861 5044.5 10939 T5 Control (No Zn) 86.48 5090 4303.0 9593 SED 2.47 173.29 178.86 290.65 CD_(5%) 7.44 522.23 539.01 875.92 CV (%) 4.64 5.30 6.36 4.78

TABLE 10 Effect of zinc compositions on yield components of rice Pan- Pan- Filled 1000 Prod. icle icle grains/ grain Tillers/ Length Wt pan- wt S. No Treatment m² (cm) (g) icle (g) T1 Zn HEDP @ 1 g/lt. 395 22.2 2.60 107 24.7 T2 Zn HEDP @ 2 g/lt 410 22.9 2.89 120 25.2 T3 Zn EDTA @ 1 g/lt. 396 22.3 2.60 105 24.6 T4 Zn EDTA @ 2 g/lt. 403 22.6 2.79 116 25.3 T5 Control (No Zn) 363 21.2 2.14 94 22.8 S.Ed 8.90 0.31 0.08 3.22 0.69 CD_(5%) 26.81 0.95 0.25 9.69 2.09 CV (%) 3.92 2.45 5.52 5.15 4.90

The above experiment showed that rice grain yield improved significantly with zinc (foliar) application at 20, 40 and 60 days after planting. Both the zinc compositions, Zn-HEDP and Zn-EDTA, improved the grain yield significantly compared to unsprayed control. Straw yield also responded similarly due to zinc compositions and doses. Plant height was significantly improved due to the higher dose of both Zn-HEDP and Zn-EDTA compositions compared to their lower dose and unsprayed check. Similarly, rice plant total biomass at both the doses of Zn-HEDP and higher dose of Zn-EDTA recorded significantly higher biomass compared to the lower dose of Zn-EDTA and the unsprayed check.

Productive tillers/m² panicle length and panicle weight were influenced in similar way as shown in Table 10. Zinc application irrespective of dose or composition improved productive tillers, panicle length and panicle weight significantly compared to unsprayed check. However, filled grain number per panicle and 1000-grain weight increased significantly with zinc application and with increasing dose with both the compositions.

The above results indicated that use of Zn-HEDP as foliar spray applied at 20, 40 and 60 DAT, improved rice yields significantly by positively influencing the yield parameters, viz. productive tillers/m², panicle length and weight, filled grains per panicle and 1000 grain weight.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The details of the invention, its object and advantages explained hereinbefore is to be understood that the invention, as fully described herein is not intended to be limited by the objects mentioned herein. 

I claim:
 1. A process for preparing a chelated fertilizer composition using compounds comprising disodium salt of Hydroxy Ethylidene Di Phosphonic Acid (Na₂ HEDP) and ZnSO₄.H₂O (Zinc sulphate monohydrate), comprising the steps of: dissolving Na₂ HEDP in water; heating the dissolved mixture up to 100° C. in a non-stick temperature controlled vessel/reactor; adding ZnSO₄.H₂O and stirring to obtain mixture containing Zn-HEDP and P₂O₅; maintaining the temperature at 100° C. and stirring the mixture until liquid portion evaporates; and drying a composition thus obtained using drier to secure moisture free powder composition containing 17% Zn-HEDP and 21% P₂O₅.
 2. A process for preparing a chelated fertilizer composition using compounds comprising disodium salt of Hydroxy Ethylidene Di Phosphonic Acid (Na₂ HEDP) and ZnO (Zinc Oxide), comprising the steps of: dissolving Na₂ HEDP in water; heating the dissolved mixture up to 100° C. in a non-stick temperature controlled vessel/reactor; adding ZnO and stirring to obtain mixture containing Zn-HEDP and P₂O₅; maintaining the temperature at 100° C. and stirring the mixture until liquid portion evaporates; drying a composition thus obtained using drier to secure moisture free powder composition containing 23% Zn-HEDP and 29% P₂O₅; adding 10% by weight dispersal powder; and mixing in blender to obtain 21% Zn-HEDP and 26% P₂O₅. 